Strains Of Microorganisms Research Articles

Probiotic Products: Appropriate Technologies for Control of Infectious Animal Diseases in the Face of Climate Change and Antimicrobial Resistance

Probiotic products are products which contain probiotics; these are live non-pathogenic microorganisms which provide health benefits to the host when administered in adequate amounts. Currently the world is facing a climate change crisis which among other things, leads to alteration of the abundance, distribution and transmission of animal pathogens leading to increased incidences of animal diseases. Moreover, the world is facing a crisis of development of antimicrobial resistance (AMR) by many strains of pathogenic microorganisms. For many decades conventional technologies which have been used for control of infectious diseases in animals include vaccines, antimicrobials, acaricides, and antihelmintics. The AMR crisis has made antimicrobials not to be a reliable technology for control of some infectious diseases caused by pathogenic microorganisms. In attempts to look for alternative technologies other than vaccines, acaricides, and antihelmintics for control of infectious diseases in animals, many studies have been conducted to determine prophylactic efficacy of many strains of probiotics against the diseases. The objective of this paper is to review prophylactic efficacy of probiotic products against infectious animal diseases and provide insights on mechanisms of action of probiotics. Reports of prophylactic efficacy of probiotic products against animal diseases, and mechanisms of action of probiotics were searched using google search engine. After assessment of the reports; appropriate ones were selected, summarized, and globally synthesized. Many reports reporting significant prophylactic efficacy of probiotic products against infectious animal diseases were found. However, most studies focused on bacterial diseases of the digestive system. More studies focusing on bacterial, viral, and protozoal diseases of the digestive and other body systems of animals are recommended in order to get more data on the spectrum of activity of probiotics. Based on this review it is concluded that probiotic products have significant prophylactic efficacy against infectious animal diseases. The products are appropriate for use as alternative technologies to antimicrobials for control of infectious animal diseases in the AMR crisis. They are also appropriate for use in climate adapted livestock farming because apart from contributing to enhancement of animal health and productivity, they contribute to adaptation of some of the impacts of climate change in livestock farming (particularly increased incidences of animal diseases) by enhancing the resilience of livestock to diseases; and climate change mitigation by decreasing greenhouse gas intensity through enhanced animal health.

Antibiotic Sensitivity Pattern of Isolates from Restaurant Wastewater

Background: This study was carried out to investigate the presence of antibiotic resistance in restaurant wastewater collected from three restaurants within the University environs. Methodology: The samples were examined microbiologically and tested for antibiotic sensitivity by conventional methods. The microbial load in the restaurant wastewater ranged from 1.18 x 105 – 9.9 x 105 and 2.9 x 105 -7.9 x 105 after tyndallization. The microbial isolates were identified to be Corynebacterium sp., Pseudomonas sp., Klebsiella sp., Staphylococcus sp., Bacillus sp., and the fungal isolates were Hafnia, and Providencia. The highest percentage of occurrence was observed for Corynebacterium (38%), and the lowest occurrence was observed for Staphylococcus, Bacillus, and Providencia (6.9%). Antibiotic susceptibility of the microns was assayed according to the Kirby- Bauer disc diffusion method. Results: The result of this study indicated that out of all the strains of microorganisms isolated, the highest multi-resistant pattern was found with Corynebacterium, it was resistant to nine isolates out of the ten isolates it was tested for, was susceptible to only Chloramphenicol (30µg). Pseudomonas was the least susceptible, being resistant to only three antibiotics namely Ciproflox (10µg), Amoxicillin (30µg), and Streptomycin (30µg). The results showed 50% resistance to Norobiocin (30µg), Ciproflox (10µg), Gentamicin (10µg), Amplicox (30µg), Streptomycin (30µg); 40% resistance to Levomycin (30µg), Rifampicin (10µg), 30% resistance to Amoxicillin (30µg), and 20% resistance to Chloramphenicol (30µg) and Erythromycin (10µg). Conclusion: With the current emphasis on environmental health and water pollution issues, there is an increasing awareness of the need to dispose of wastewater safely and beneficially by ensuring they are treated properly before reuse or final disposal into water bodies.

Application of metagenomic next-generation sequencing (mNGS) to describe the microbial characteristics of diabetic foot ulcers at a tertiary medical center in South China

BackgroundDiabetic foot ulcers (DFUs) are characterized by dynamic wound microbiome, the timely and accurate identification of pathogens in the clinic is required to initiate precise and individualized treatment. Metagenomic next-generation sequencing (mNGS) has been a useful supplement to routine culture method for the etiological diagnosis of DFUs. In this study, we utilized a routine culture method and mNGS to analyze the same DFU wound samples and the results were compared.MethodsForty samples from patients with DFUs at a tertiary medical center in South China were collected, the microorganisms were identified with mNGS and routine culture method simultaneously.ResultsThe results showed that the positive detection rate of microorganisms in DFUs with mNGS was much higher (95% vs. 60%). Thirteen strains of microorganisms were detected with routine culture method, and seventy-seven strains were detected with mNGS. Staphylococcus aureus was the most common microorganism detected with culture method, while Enterococcus faecalis was the most common microorganism detected with mNGS. The false negative rate of the culture method was 35%, that was, 14 samples with negative results with culture method were found to be positive with mNGS.ConclusionThe mNGS method had a higher positive detection rate and identified a broader spectrum of microorganisms in DFUs, thus, mNGS provided a more comprehensive understanding of the microbiome of DFUs to facilitate the development of timely and optimal treatment.Trial registrationThe study was conducted in accordance with the Declaration of Helsinki and approved by the Ethical Review Committee of the Fujian Medical University Union Hospital (approval number 2021KY054).

Amazonian Microorganism Strains Improve Physiological Performance to Oil Palm Seedlings Growth Promote

Amazonian Microorganism Strains Improve Physiological Performance to Oil Palm Seedlings Growth Promote

ВИДОВОЙ СОСТАВ И АНТИБИОТИКОРЕЗИСТЕНТНОСТЬ БАКТЕРИАЛЬНЫХ ИЗОЛЯТОВ, ВЫДЕЛЕННЫХ ОТ ЖИВОТНЫХ ОМСКОЙ ОБЛАСТИ

The purpose of research is to study the species composition of microorganisms isolated from agricultural and small domestic animals of the Omsk Region in 2022, to determine the sensitivity to antibacterial agents of prevailing crops in the general structure of isolates. The bacteriological study was carried out on the basis of the Omsk Regional Veterinary Laboratory according to the current methods for the isolation, identification and determination of the sensitivity of microorganisms to antibacterial drugs. The material of the study was samples of clinical material (106) taken from agricultural and small domestic animals in various geographical regions of the Omsk Region. Cultures of etiologically significant microorganisms belonging to the genera were isolated: Staphylococcus, Escherichia, Proteus, Enterococcus, Streptococcus, Enterobacter, Bordetella, Citrobacter, Salmonella, Morganella, Neisseria, Malassezia, Listeria, Bacillus, Klebsiella. In the general structure of the obtained cultures microorganisms of the genus Staphylococcus (36 %) and Escherichia dominated (22 %). Based on the data obtained, a study was made of the antibiotic resistance of the isolated microorganisms of the genus Staphylococcus and the species Escherichia coli to antibacterial agents by the disk-diffusion method on the Givental-Vedmina medium. As a result of the study, it was found that the highest resistance of these microorganisms was recorded to cephalexin, streptomycin, pefloxacin, kanamycin. Further study of the phenomenon of antibiotic resistance of microorganisms opens up great opportunities for improving the effectiveness of therapy for bacterial animal diseases. Specialists in clinical veterinary practice need to take into account the sensitivity to antibiotics in each case of animal disease with bacterial diseases. Such a conscious approach to prescribing antibiotic therapy in the future will lead to a decrease in the accumulation of antibiotic resistance genes among circulating strains of microorganisms.

Deep generative modeling of annotated bacterial biofilm images

Biofilms are critical for understanding environmental processes, developing biotechnology applications, and progressing in medical treatments of various infections. Nowadays, a key limiting factor for biofilm analysis is the difficulty in obtaining large datasets with fully annotated images. This study introduces a versatile approach for creating synthetic datasets of annotated biofilm images with employing deep generative modeling techniques, including VAEs, GANs, diffusion models, and CycleGAN. Synthetic datasets can significantly improve the training of computer vision models for automated biofilm analysis, as demonstrated with the application of Mask R-CNN detection model. The approach represents a key advance in the field of biofilm research, offering a scalable solution for generating high-quality training data and working with different strains of microorganisms at different stages of formation. Terabyte-scale datasets can be easily generated on personal computers. A web application is provided for the on-demand generation of biofilm images.

Analysis of antibiotic sensitivity of clinical strains of microorganisms with the Russian Mueller–Hinton broth

Introduction. One of the reasons for spreading antibiotic-resistant microorganisms is the uncontrolled use and inadequate empirical prescription of antibiotics which is not based on the results of the pathogen sensitivity testing. The broth dilution method and one of its implementation options, the reference microdilution method, in contrast to the disk diffusion method, allows testing virtually all pathogen-antibiotic combinations. To realize the method, a production technology of Russian Mueller–Hinton broth (MHB-Obolensk) has been developed under the import substitution program. The aim. To evaluate the quality of the developed domestic Mueller–Hinton broth in comparative tests with its imported analog BD BBL (MHB-BD) in testing clinical strains of microorganisms, including microorganism–antibiotic combinations pairs which cannot be reliably investigated by the disc diffusion method. Materials and methods. The study investigated the sensitivity of 47 clinical strains of Gram-positive and Gram-negative bacteria to antibiotics of various functional groups using the broth microdilution method with MHB-Obolensk and MHB-BD. Results. The MICs values of antibiotics for clinical strains obtained with the developed and control media did not practically differ from each other or differed by +/– one dilution. The difference by two two-fold dilutions was noted when testing Enterococcus faecium–ampicillin, Klebsiella pneumoniae–meropenem, Pseudomonas aeruginosa–levofloxacin and Staphylococcus aureus–ciprofloxacin combinations. For the first two combinations, the MIC values were lower in MHB-Obolensk, and for the last two, they were higher than in MHB-BD. The differences obtained did not affect the clinical categories of sensitivity. Conclusion. The antibiograms of clinical strains in developed Russian Mueller–Hinton broth was obtained, which did not differ from those for the comparison medium. MHB-Obolensk complies with the requirements of national and international standards and can be used to reliably test, among other things, current combinations of microorganism–antibiotic pairs that cannot be studied using the disk diffusion method.

Biofilm as a supracellular organization of pathogenic bacteria

The high frequency of resistance to antibiotics among bacterial clinical isolates necessitates the discovery of new targets for suppressing the pathogenicity of microbes without stimulating their resistance. The studied sources suggest that this can be achieved by targeting the determinants of virulence. The search for new active substances with anti-biofilm activity based on the analysis of literature data on the structure of bacterial biofilms, mechanisms of their resistance to antimicrobial agents was the purpose of this work. An electronic search was conducted in Medline (PubMed interface), Scopus, and Web of Science between 2011 and July, 2024 using the keywords: biofilms, antibiotic resistance, Quorum sensing, persisters. 30 sources were selected, 85 were processed. The subject of the search was: microbial landscape of hospital strains of microorganisms, biofilm formation by microorganisms – pathogens of infectious diseases, regulation of virulence factors in bacterial biofilm. Studies of recent years have established that many pathogenic bacteria produce signal molecules for cellular communication. This signaling system is called Quorum sensing (QS) and it depends on the density of the bacterial population and is mediated by signaling molecules called pheromones or autoinducers (AI). Bacteria use QS to regulate activities and behavior including competence, conjugation, symbiosis, virulence, motility, sporulation, antibiotic production and biofilm formation. Researches aimed at bacterial communicative signals and suppressing QS demonstrate a fundamental approach to forming competitive microbial communication. The search, synthesis, and development of drugs based on modified autoinducers of various natures can lead to a breakthrough in the field of antibacterial therapy of infectious diseases, as well as surgical purulent postoperative complications. The pro­cessed literature describes a number of hypotheses regarding the participation of "toxin-antitoxin" systems that control the growth and metabolism of bacteria in the stimulation of the formation of persister cells. The simultaneous acquisition of resistance to many antibacterial factors, including physico-chemical ones, is suggested. Therefore, there is an increased attention of scientists to the study of the anti-biofilm effect of new compounds and drugs capable of influencing energy or metabolic processes in cells, as well as substances that do not require a metabolically active target. The review illustrates general modern approaches to the use of QS chains in pathogenic bacteria as new therapeutic targets.

Septic shock in the intensive care unit of a multidisciplinary hospital

The objective of the study was to assess the prevalence, etiology, and outcomes of intensive care in patients with septic shock in the ICU of a multidisciplinary hospital.Materials and methods. A single-center, retrospective, cohort study was conducted involving 398 patients with septic shock who were hospitalized in the ICU over a one-year period. Diagnosis of septic shock, as well as a complex of intensive care, were carried out according to the criteria proposed by the recommendations of the Surviving sepsis campaign (2021). Antibacterial therapy was prescribed based on the Guidelines «Diagnosis and antimicrobial therapy of infections caused by multidrug-resistant strains of microorganisms» (2022)Results. The proportion of patients with septic shock was 7.4% of the entire population hospitalized in the ICU. The hospital mortality rate was 25%. The dominant loci of infection in patients with septic shock were the abdominal cavity (33%) and lungs (32.4%). The microbial landscape was dominated by gram-negative flora (66%), among which in 35% of cases, Klebsiella pneumoniae was characterized by resistance to the antibacterial drugs used. Combined antibacterial therapy was received by 84% of patients.

ANTAGONISTIC ACTIVITY OF BLACK SEA ACTINOBACTERIA AGAINST PHYTOPATHOGENIC MICROORGANISMS

The biological method of plant protection is an environmentally safe and priority form in long-term programs to combat pathogens and one of the important tools for the transition to organic and ecological agriculture in Ukraine. Aim. To define the antagonistic activity of the Black Sea actinobacteria against phytopathogenic microorganisms. Methods. The antagonistic activity of 35 strains of actinobacteria isolated from different biotopes of the Odesa Bay of the Black Sea against collection and isolated from affected cereal plants phytopathogenic microorganisms was determined by the block method after preliminary cultivation of actinobacteria on Gause 2 medium for 12 days at 28±1 °C. The antagonistic activity of extracted secondary metabolites of Streptomyces ambofaciens ONU 1016 and S. ambofaciens ONU 561 against Fusarium oxysporum strains was determined by the disk-diffusion method. Results. Of the 35 studied, the growth of at least one strain of phytopathogenic bacteria and fungi was inhibited by 77.1% and 65.7% of actinobacterial strains, respectively. The sizes of the zones of no growth of sensitive collection strains of bacteria ranged from 15.3±0.1 mm to 29.6±0.3 mm, and of bacterial strains isolated from affected plants – from 14.5±0.1 mm to 25.7±0.3 mm under the action of antagonistically active actinobacteria. This indicator for collection strains of fungi was determined in the range from 16.0±0.2 mm to 33.5±0.3 mm, for isolated strains of fungi – from 15.0±0.1 mm to 29.3±0.3 mm. S. ambofaciens ONU 1016 and S. ambofaciens ONU 561 showed the best activity against all strains of phytopathogenic microorganisms, in particular against F. oxysporum isolated from affected plants, the zones of no growth of more than 80.0% of the strains of which exceeded 20.0 mm. The extracted secondary metabolites of both S. ambofaciens strains inhibited the growth of the collection and isolated fusarium strains. The zones of no growth of fungi varied widely and depended, primarily, on the strains of fusarium, streptomyces, the concentration of extracts, and the period of recording the results. The minimum inhibitory concentrations of extracted metabolites of S. ambofaciens ONU 1016 and S. ambofaciens ONU 561 against the isolated strains of F. oxysporum were 250 μg/ml – 500 μg/ml and 250 μg/ml – 100 μg/ml, respectively. Conclusions. Actinobacterial strains isolated from sponges and mussels of the Odesa Bay of the Black Sea are antagonistically active against phytopathogenic microorganisms, in particular the fungi F. oxysporum. Collection strains of phytopathogens are more sensitive to the action of sea actinobacteria than strains isolated from affected plants. Strains S. ambofaciens ONU 1016 and S. ambofaciens ONU 561, which showed high antagonistic activity, can be recommended for the creation of a microbial preparation for protecting plants from bacterial and fungal pathogens.

Changes in metabolite profiles in solid fermentation of glutamate waste treatment solution by Aspergillus niger and Candida tropicalis.

Glutamate wastewater poses a great environmental challenge to the monosodium glutamate production industry. However, its treatment solution is rich in crude protein, which has the potential to be developed as a new protein source for animal feed. Given that the fermentation process generates functionally different metabolites, this study innovatively utilized two strains of feed microorganisms, Aspergillus niger and Candida tropicalis, to perform solid-state fermentation of glutamate wastewater treatment solution. The aim was to investigate and analyze the metabolite profiles during fermentation. The significant differences in metabolite profiles between the samples were determined using correlation analysis, principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), variable importance in projection (VIP) analysis, Kyoto Encyclopaedia of Genomes (KEGG), and Human Metabolome Data Bank (HMDB) analysis. These variations were mainly manifested in essential feed components, such as amino acids, peptides, and their analogues. These included Ile-Pro-Asn, Pro-Gly-Val, alanylvaline, histidylisoleucine, Lys-Leu-Tyr, Ile-Arg, glycyl-leucine, leucyl-lysine, N-palmitoyl histidine, alanylisoleucine, L-glutamate, N-methylisoleucine, lsoleucylproline, DL-m-tyrosine, lsoleucyl-threonine, phenylalanine amide, carboxyethyllysine, N6-acetyl-L-lysine, citrulline, N-alpha-acetyl-L-lysine, N(6)-methyllysine, and L-aspartate-semialdehyde. This study investigates the metabolite profiles of glutamate wastewater treatment solutions after co-fermentation with Aspergillus niger and Candida tropicalis using solid-state fermentation. These findings provide a new strategy for efficiently utilizing glutamate wastewater treatment solutions.

Cellulolytic potential of new strains of soil streptomycetes

In order to obtain new strains of cellulolytic microorganisms for use in technologies for processing plant and other cellulose-containing waste, four new bacterial strains of the genus Streptomyces have been isolated from various sources. In tests with Congo red, the isolates’ ability to degrade carboxymethylcellulose (CMC), microcrystalline cellulose (MCC) and natural cellulose–containing materials – straw, birch and oak sawdust was determined. The activity of cellulase was quantified during fermentation of straw. On media with each of the model carbon sources, the radial growth rate was determined as an indicator characterizing the ability of isolates to colonize various substrates. The conjugate characteristic of cellulase activity and radial growth rate on substrates of various natures made it possible to assess the prospects for further use of the studied strains as destructors of cellulose-containing waste. The strain Streptomyces thermocarboxydus T1-3 was the leader in the studied sample, characterized by the most active enzymatic hydrolysis of all model cellulose sources, a high radial growth rate (up to 87±3 microns/hour), and the achievement of maximum cellulase activity (171.25±8.13 U/ml) during straw fermentation within 24 hours.

Patterns of biofilm formation by members of <i>Listeria</i>, <i>Salmonella</i>, and <i>Pseudomonas</i> at various temperatures and the role of their synergistic interactions in the formation of biofilm communities

Biofilm formation on abiotic surfaces in the food sector is a major public health concern. In fact, biofilms represent a constant source of pathogens such as Listeria monocytogenes and Salmonella sp. The ability for the formation of multispecies biofilms by pathogens and spoilage microorganisms poses a serious danger in the production of safe products and is one of the reasons for the stable circulation of microorganisms in meat processing plants. During the work, 46 strains of microorganisms isolated from industrial environments and food products were tested for the ability to form biofilms at different temperatures. The analyzed pathogenic strains (Listeria monocytogenes, Salmonella sp.) and spoilage microorganisms (Pseudomonas sp.) had adhesion to the abiotic surface with subsequent formation of a persistent biofilm. Low positive temperature was not a limiting factor in the ability to form biofilms. After 24 hours of incubation, representatives of bacteria of the genera Listeria and Salmonella sp. formed persistent biofilms at (4°C). The ability to form biofilms on various abiotic surfaces found in the meat industry (tiles, glass, plastic) has been demonstrated. The synergistic interaction of representatives of the genera Listeria, Salmonella and Pseudomonas during the formation of mixed biofilms at 4°C was studied. Combinations of a pathogen and a member of the genus Pseudomonas differed significantly in the intensity of biofilm formation compared to combinations of two pathogens. This indicates the importance of this species in synergistic interactions among microorganisms.

Microorganism Strains, Environmentally Friendly and Biological Preparations Against Meloidogyne hapla Chitwood, 1949 and Their Impact on Fruit Quality and Tomato Crop Structure.

The primary aim of this research was to study the effectiveness of various strains of antagonist microorganisms and biological preparations against Meloidogyne hapla, in addition to their impact on the quality of tomato fruits and crop structure. Four microorganism strains and three registered environmentally safe nematicides were used in the experiment presented herein. The results showed that the strains Paecilomyces lilacinus F-22BK/6 and Arthrobotrys conoides F-22BK/4 had the greatest biological efficacy, reducing the number of galls on tomato plants by 91.8% and 88.4%, values comparable with the results of the chemical control Vydate 5G. The Metarhizium anisopliae F-22BK/2 and Arthrobotrys conoides F-22BK/4 treatments showed the best results, increasing the fruit weight by 8.6% and 9.9%, in addition to increasing the tomato yield by 5.0% and 13.3%. These strains contributed to an increase in sugar content, whereas the concentration of vitamin C was reduced in the Trichoderma viride F-294 and Fitoverm treatments, indicating a high level of oxidative stress in the latter treatments. The results of this study confirm the prospects of using biological nematicides against phytoparasitic nematodes, which will not only enable effective control of their population but also improve the quality of agricultural products, minimizing harm to the environment and human health.

NANO-MATERIALS IN DENTAL IMPLANTS - UNDERSTANDING COMPOSITION AND BIOFILM DYNAMICS

The study showcases findings from an investigation into the chemical composition and morphology of nanocomposite materials employed in the production of dental implants. By utilizing clinical strains of microorganisms isolated from patients with implant infections (including Bacteroides fragilis, Porphyromonas melaninogenica, Actinomyces spp., and Staphylococcus aureus), the authors of the paper analyze the results of the dynamics of biofilm formation on the composite's surface. To minimize complications following surgical procedures in dentistry, the recommendations on the most advantageous research algorithm for composite materials are provided. The implications of these findings extend to the broader field of biomaterials, emphasizing the significance of a meticulous examination of the chemical and morphological attributes for enhancing the long-term success and safety of dental implants. This comprehensive approach addresses immediate concerns related to biofilm formation and provides a foundation for developing more resilient and biocompatible materials in dental prosthetics.

The effect of temperature on the activity of microorganisms in the area of the Bureiskiy Landslide

The manuscript presents the results of experimental studies of the adaptive potential of microorganisms that are part of the bacterioplankton of the surface and bottom water layers of the Bureiskoe Reservoir in the zone of the landslide that descended in the winter of 2018. In the summer of 2022, the structure and activity of microbial complexes from area near the landslide were studied. More than 60 strains of microorganisms of different physiological groups were isolated. On the example of 4 strains isolated from different habitats (above and below the landslide body, surface and bottom layers of water) after 30 days of freezing at a temperature of –18°C, their viability and activity in the utilization of easily available nitrogen-containing organic substances were shown. In experimental cyclic freezing-thawing, two variants of thawing were used: slow thawing in a refrigerator from –18°C to +4°C; fast defrosting over a wide temperature range from –18°C to +23°C (at room temperature). Regardless of location, all strains grew vigorously in vitro with use of a readily available peptone carbon source before and after freezing. The maximum activity on peptone was shown by strain 40 BB (below the landslide body, bottom water) in the absence of substrate change. Utilization of peptone as a source of amino acids and peptides could be accompanied by activation of the protective function against cold stress. The selected strains of microorganisms differed in their ability to transform sodium humate molecules depending on the conditions of the freeze/thaw cycles. According to the spectral characteristics, significant changes in the aliphatic and aromatic components of the humate molecule occurred with the participation of strains 45 AB and 40 BB isolated from the bottom water. These strains were more active at low thawing temperatures, which actually corresponded to the in situ temperature of the bottom water layers, which is 4–6°C. Strain 13 BS from surface water sampled below the landslide body is characterized by active transformation of the aromatic component of humic substances in a wide range of thawing temperatures (from –18 to +23°C). The results indicate that in different regions during the thawing of permafrost and the influx of specific organic substances the specific mechanisms of formation of the quality of natural waters may manifest.

Synthesis and Antibacterial Activity of New 6″-Modified Tobramycin Derivatives.

Objectives: Aminoglycosides are one of the first classes of natural antibiotics which have not lost relevance due to their broad spectrum of action against Gram-positive, Gram-negative bacteria and mycobacteria. The high growth rate of antimicrobial resistance (AMR) together with the severe side effects of aminoglycosides increase the importance of developing improved semisynthetic derivatives. Methods: In this work, we proposed a synthetic route to new tobramycin derivatives modified at the 6″-position with aminoalkylamine or guanidinoalkylamine residues. Results: The antibacterial activity of the new compounds against reference strains of microorganisms was comparable to the parental tobramycin. In striking contrast to tobramycin (resistance index, >256), its 6″-modified derivatives were significantly more potent against resistant clinical isolates of P. aeruginosa strains (resistance index = 4-16) and they demonstrated a promising AMR circumvention in E. coli strains associated with mutations in the fusA gene encoding elongation factor G. All the obtained tobramycin derivatives exhibited reduced cytotoxicity for the eukaryotic HEK293T cells compared to the tobramycin and thereby they potentially may have improved therapeutic index. The proposed modification of the 6″-position of tobramycin does not change the mechanism of aminoglycoside's antibacterial activity: new compounds induced translation errors which resulted in the inhibition of protein synthesis in bacterial cells. Conclusions: Taken together, we can suggest that further modifications of the 6″-position of tobramycin may be beneficial for circumvention of AMR to aminoglycosides or used for conjugation with other molecules of interest.

Productive Potential of Bacillus and Pseudomonas Strains Grown in the Presence of Iron, Zinc and Copper Salts

Identifying and obtaining biotechnological solutions for agriculture, such as the development of antimicrobial agents with highly effective biological properties and plant productivity stimulants, are sustainable solutions, friendly to the environment and harmless to humans. Due to the importance of iron and zinc for plant growth and development, as well as copper used to protect plants against a wide range of fungal and bacterial diseases, studies have been initiated to identify and select new strains of microorganisms with the potential to synthesize bioactive substances when grown in the presence of iron, zinc and copper-based compounds. Thus, the effect of iron, zinc and copper compounds on the productivity of three strains of Bacillus sp. bacteria and three strains of Pseudomonas sp. with antimicrobial action on phytopathogens was tested.

Biodegradation of commercial polyester polyurethane by a soil-borne bacterium Bacillus velezensis MB01B: Efficiency, degradation pathway, and in-situ remediation in landfill soil

Polyurethane (PU), a widely used and durable plastic, persists in the environment, resulting in significant waste management challenges. Therefore, developing eco-friendly degradation technologies, such as screening for efficient biodegrading microorganism strains, is urgently needed to address this issue. Bacillus velezensis MB01B, an efficient polyester PU-degrading bacterium, was isolated from landfill soil and demonstrated the ability to degrade 91.4% of 0.75% Impranil DLN within 24 h under the optimal conditions (30.5 °C and initial pH 6.5). To assess the degradation capability of MB01B, three PU substrates of increasing complexity—Impranil DLN film, polyester thermoplastic polyurethane (TPU) film, and commercial PU desk mat—were tested; after 30 days, weight losses of 24.8%, 18.3%, and 5.4% were observed, respectively. In addition, SEM images showed significant morphological changes on the surface of these PU materials after treatment with MB01B. FTIR analysis of Impranil DLN films following degradation showed reductions in key functional groups (ester and urethane); and the identification of neopentyl glycol and 1,6-hexanediol as degradation intermediates suggested MB01B possesses the capability to hydrolyze ester and urethane bonds. Concurrently, genome sequencing combined with RT-qPCR identified several enzymes, including urethanases and esterases/lipases, involved in PU degradation. Based on these results, the pathway for MB01B to degrade Impranil DLN was inferred. Finally, MB01B was successfully formulated into a solid microbial inoculum with favorable storage properties and used for in-situ degradation of the commercial PU materials (Impranil DLN films, TPU films and PU desk mats) in landfill soil, underscoring its potential for the in-situ biological treatment of PU plastic wastes.

In silico Analysis of the Stability of Ribosomal Protein S1 from Various Strains of the Pathogenic Microorganism Staphylococcus aureus.

The pathogenic microorganism Staphylococcus aureus, one of the representatives of the staphylococcus family, is capable of developing resistance to antibiotics and antiseptics. The largest ribosomal protein, S1, from S. aureus contains four structural S1 domains, and short peptides synthesized based on its sequence have amyloidogenic and antimicrobial properties (antimicrobial peptides). In this work, in silico analysis of all available ribosomal protein S1 sequences from various S. aureus strains allowed us to identify residues that are characteristic of specific strains. Based on data from the I-Mutant service, changes in the stability of ribosomal protein S1 from various S. aureus strains were predicted. The results obtained will be used in the future for targeted mutations in the design of new antimicrobial peptides based on ribosomal protein S1.